A: Yes. Create a separate partition (APFS for newer macOS, HFS+ for Yosemite) and install Yosemite on the second volume. Use the Startup Disk preference pane or hold Option during boot to switch.
If you own a vintage Mac (such as a 2008–2014 MacBook, iMac, or Mac mini) that cannot officially run Catalina or later, or if you need to run legacy software like Adobe CS6 or older audio plugins, Yosemite 10.10.5 is often your best bet. This article will walk you through everything you need to know about safely obtaining, verifying, and installing the official DMG file. Before you download, it is crucial to understand what version 10.10.5 actually is. Apple released OS X Yosemite (version 10.10) on October 16, 2014. It introduced a flat design, Continuity features (Handoff, Phone calls on Mac), and a redesigned Notification Center. The 10.10.5 update, released on August 13, 2015, was the final supplemental update for Yosemite. mac os x yosemite 10.10 5 download dmg
Introduction: Why Yosemite Still Matters A: Yes